Synthesis method for cefaclor key intermediate
A cefaclor and synthesis method technology, applied in the field of synthesis of pharmaceutical intermediates, can solve the problems of pollution, low total yield, etc., and achieve the effects of easy availability of raw materials, low cost, and reduced sewage treatment costs
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Embodiment 1
[0031] The synthesis of embodiment 1 compound 3
[0032] Add 80mL of dichloromethane, 37.3g of compound 1 (100mmol), 19.3g of diphenylmethanol (105mmol), 16.6g of pyridine (210mmol) into a 250mL four-neck flask, control the temperature at 30°C, and add methanesulfonyl chloride dropwise within 30min 12.0g (105mmol), after the dropwise addition, continue to stir for 2h, then dropwise add 20% sulfuric acid aqueous solution, adjust the pH to about 7.0, separate the organic phase, extract the aqueous phase with 20mL of dichloromethane, and combine the organic phases. Add 3.7g of supported catalyst (according to literature Maurizio Benaglia, Mauro Cinquini, Franco Cozzi and Graziella Tocco.Synthesis of a poly(ethylene glycol)-supported tetrakis ammonium salt: a recyclable phase-transfer catalyst of improved catalytic efficiency. Tetrahedron Letters, 2002, 43, 3391–3393. Preparation), the 0.5g Na 2 WO 4 2H 2O and 0.1 g of 85% phosphoric acid were dissolved in 11.9 g of 30% hydroge...
Embodiment 2
[0033] The synthesis of embodiment 2 compound 4
[0034] Add 150mL of toluene, 51.7g of compound 3 (100mmol), and 13.0g of trimethyl phosphite (105mmol) into a 250mL four-necked flask, purging and replacing the reaction system with nitrogen for 3 times, then raising the temperature to 110°C, and reflux for 12h (Reaction monitored by TLC). Concentrate under reduced pressure at 50°C. After the content becomes viscous, add 150mL of methanol, heat to dissolve, cool down and crystallize, stir at 0-5°C for 1h, filter with suction, and wash the filter cake with 10mL of ice-methanol to obtain 42.6g of compound 4 as a white solid. The HPLC purity was 99.0%, the melting point was 85.9-86.5°C, and the yield was 88.2%.
Embodiment 3
[0035] The synthesis of embodiment 3 compound 6
[0036] Add 150mL of dichloromethane, 30mL of methanol, and 24.2g of compound 4 (50mmol) into a 250mL four-necked bottle, cool down to -35°C, pass through ozone until the reaction solution turns blue, and then pass through nitrogen until the tail gas is non-oxidizing (KI starch The test paper does not change color), add 6.5 g (52.5 mmol) of trimethyl phosphite dropwise within 30 minutes, after the dropwise addition is completed, continue to stir for 2 hours. Add 90 mL of water, separate the organic phase, extract the aqueous phase with 30 mL of dichloromethane, and combine the organic phases. Concentrate the organic phase under reduced pressure at 30°C. After the content becomes sticky, add 150mL dichloromethane and 10.0g (52.5mmol) p-toluenesulfonyl chloride, cool down to 5°C, add 9.2g (105mmol) morpholine dropwise within 30min, continue React for 7h (TLC monitors the reaction). Add 30 mL of water, separate the organic phase,...
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